tachypnoeaPronunciation: /ˌtakɪpˈniːə/ (US tachypnea)Definition of tachypnoea noun [mass noun] Medicine abnormally rapid breathing. Origin: late 19th century: from tachy- 'swift' + Greek pnoē 'breathing'tachypnoea in other Oxford dictionaries Definition of tachypnoea in the US English dictionary